I know Peter Blasser uses piezos as control input on the Shnth, and I’m assuming a few other instruments - I have no idea personally how it’s done, but I imagine a softer piezo on a flexible-ish surface could be used for very expressive CV control. Don’t flex it too much though, or it will snap
And then check out Tom Nunn’s work - a buddy of mine has one of his handmade instruments, which is basically a bunch of brass rods cut to different lengths and hammered into a resonating board with a contact mic on it, and you play it with combs! Pretty cool.
In his instruments its super simple, it’s literally just a piezo connected as a CV source!
(probably with some clipping/limiting inside the standalone instruments), but a piezo will produce a positive (and negative) voltage passively, so you don’t need a lot to get going. The only thing is that it can produce a pretty big spike as well, hence the potential limiting.
Unless I’m mistaken, I think the barre controller is literally 4 piezos connected to four jacks, and that’s it.
I’ve played with film piezos a bit, both as a contact mic, and as a CV source (controlling Blasser synths). The output level from them is waaaaaay lower than a piezo disc, so you’ll a preamp/buffer for sure.
If you’re looking for info on different types of contact mics, I re-recommend this book:
yes,This is one of the Bart Hopkin books - great stuff. in it he discusses a potential slack coil type contact pick up but i have not made one. Just wondered if anyone has seen/used products like this out there . or also wondering if their are other alternatives to the peizo crystal.??
aha! Just thinking about this question again I remembered another twist on the theme (not strictly speaking a contact mic) - the bass pickup stompbox:
I was gonna build one of these, picked up a bass pickup very cheap but realised the BC license plates of my now-defunct crappy car are aluminium - d’oh!
Anyway a lightbulb just went off, realised it’s another use for 19" rack blank… Nice how everything comes together (sometimes)
I seconds everyone that has mentioned that as decent preamp is key if you want accurate representation of sound…I’ve also made the mint box preamp Rodrigo mentioned, it works well in my experience for capturing low pitched objects, but didn’t sound great for things like a snare drum.
The Alex rice preamp design is fantastic, and a small 2 person company in Chicago is now manufacturing kits - http://zeppelindesignlabs.com/product/cortado-balanced-piezo-contact-mic/
The kits are super easy…I made one of these on perforated and the compact size of the ZD model and already matched JFETs are well worth 25 dollars in my mind. It DOES require phantom power. ZD also sells a DIY phantom power supply that runs off a 9v and works really well. You can go ultra dork like me and put them all into one tidy box. This system works well for me since I can make numerous different sizes and shapes, and lengths of contact miss and run them through one preamp. The altoids box contains the PP and the circuit wrapped in copper tape is the preamp. Good luck!
I have some contact mics I’ve made myself and coated in plastic-dip. When I record them into my field recorder, I find using an impedance transformer improves the bottom end considerable (my Tascam doesn’t have a hi-z input). I use a HOSA MIT-129 http://hosatech.com/product/mit-129/
I’ve been looking into ears recently and after seeing this video https://youtu.be/Bv6nDi7i-S8?t=667 it convinced me that I need a contact mic. I have a drumkit and when he runs the cymbals through his modular it just sounds too cool.
I use a Radial Engineering PZ-DI for the same reason, I couldn’t believe it first time I plugged my DIY piezo in it, it’s night and day with and without it. http://www.radialeng.com/pzdi.php
They even include a variable high-pass filter for removing the excess of bottom end you’re finding back when matching impedance (it’s really useful), plus the load is variable with a 3 position switch (electromagnetic/standart/piezo), there’s a pad, an LPF and you can lift the ground.
The only downsides is that it needs +48V and it’s pricey at 220€, I know they also make a simpler, cheaper, version (SB-4), but I’m gonna try your solution for when I need to record various piezo at the same time (can’t afford multiple PZ-DIs right now…)
So you’d be plugging the impedance transformer into the xlr to mini jack adapter and then into your recorder? I think that should work, but it will be rather bulky and you may get a little signal loss from the adapters. It’s not something I’ve tried myself
Not sure if anyone mentioned this but there are 2 great tricks for getting better sound out of piezos.
First method: solder them to a mono jack in the usual way, then use a DI box. This alters the impedance and provides a good mic-level signal for any mixing desk.
Second method: some piezos have a two-part zinc contact in the middle. If you solder these to a balanced mic cable like this:
small contact = +
big contact = -
copper disc = screen
Stick an xlr on the other end and use any mixing desk or mic pre. Because the signal is sort-of balanced you can get away with very long cables without interference.
Or buy one of Jez’s mics, they sound great. Piezo foil is nice too but you have to get that from the states these days afaik. xgus
I’ve been interested and n Hanna Hartman recently https://vimeo.com/82784209 partly as I’ve recently realised that my Octatrack actually works really well by plugging my Contact Mics straight into the inputs.
I thought it could be a useful thread to document ideas or techniques useful with contact mics.
Something I always keep is old guitar strings which I tie together and use as an agitator.
whilst contact mics / piezo elements work fine plugged directly into things, two notes:
piezo elements can make REALLY large voltages. so you’re assuming the thing you’re plugging them into is correctly buffered or limited. most of the time: things are. but remember this!
I have a few of those preamps that are made to fit into guitar bodies…the very cheap ones from china ( god knows what the guitars you’d cut into for these would be like!) i house them in little wooden boxes.
added bonus of battery holder and vol&eq sliders for less than £10-ISH. The results are decently mid fi. I often use the guitar bridge style piezos as well as they come with a tiny jack at the end.
this kind of thing. I go for the ebay-cheap-china- wait a month for it.
